 - Also see diode.
A laser diode, also known as an injection laser or diode
laser, is a semiconductor device that
produces coherent radiation (in
which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it. Laser diodes are
used in optical fiber systems, compact disc (CD) players, laser printers, remote-control
devices, and intrusion detection systems.
Laser diodes differ from conventional lasers, such as the helium-neon
(He-Ne), ruby, and gas types, in several ways.
Small size and weight: A typical laser diode
measures less than one millimeter across and weighs a fraction of a gram, making it ideal
for use in portable electronic equipment.
Low current, voltage,
and power requirements: Most laser diodes require only a few milliwatts of
power at 3 to 12 volts DC and several milliamperes. Therefore, they can operate
using small battery power supplies.
Low intensity: A laser diode cannot be used for
spectacular purposes such as burning holes in metal, bringing down satellites, or blinding
aircraft pilots. Nevertheless, its coherent output results in high efficiency and
ease of modulation for communications and
control applications.
Wide-angle beam: A laser diode produces a
"cone" rather than a "pencil" of visible light or IR, although this
"cone" can be collimated using convex lenses.
| LAST UPDATED: |
04 Mar 2002
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